The present invention relates to an imaging system and method, and more particular to a system and method for constructing motion-compensated composite images.
Imaging systems, such as cameras and the like, are often vulnerable to producing blurred images due to relative movement between the imaging system and the scene which is to be acquired. Installing the imaging system upon a tripod is one way to avoid this type of degradation, although such an installation process is typically inconvenient for the user to employ.
J. Telleen et al. in “Synthetic Shutter Speed Imaging” Proc. Eurographics 2007 discloses a technique for compensating the motion of an image using layer decomposition, in which multiple images of the scene are acquired over time, each image being motion-compensated relative to a subsequently acquired image, and the images composited to form a motion-compensated image of the scene.
The number of images employed in such a technique can be set to any number, and thus it is important to employ a sufficient number to compensate for motion on the one hand, while on the other hand implementing as few images as possible so as to achieve a high signal-to-noise ratio (SNR) for the composite image. Specifically, if the total exposure time for the composite image is defined as E, and the total number of images is N, each image will have an exposure time of E/N. As the number of number of images N increases, noise contributions to each image will degrade that image's SNR, resulting in an overall SNR degradation of the final composite image, such degradation being visible as fuzziness and increased noise in the composite image. However, a large number of images may be necessary in order to provide greater motion compensation correction, e.g., when the relative motion between the imaging system and the scene is large.
What is therefore needed is a technique for constructing a motion-compensated composite image which employs an optimal number of images.